ExamTopics Logo
Mail Us[email protected]
Menu
Cisco Discussions
exam questions

Exam 642-887 All Questions

View all questions & answers for the 642-887 exam
Go to Exam

Exam 642-887 topic 1 question 13 discussion

Actual exam question from Cisco's 642-887
Question #: 13
Topic #: 1
[All 642-887 Questions]

Which of the following three statements are correct regarding IPv6 QoS? (Choose three.)

  • A. The traffic class field in the IPv6 header can be used to set specific precedence or DSCP values.
  • B. A 20-bit flow label field enables per-flow processing.
  • C. DS-TE is not supported by IPv6.
  • D. Per-hop behavior in IPv6 networks is based on EXP bits.
  • E. IPv6 QoS features are configured using the modular QoS CLI on Cisco routers.
Show Suggested Answer Hide Answer
Suggested Answer: ABE 🗳️
http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd8026004d.pdf
Cisco Systems. IPv6 QoS

AT-A-GLANCE -

RFC 2460/3697 -
Currently IPv6 provides support for QoS marking via a field in the IPv6 header.
Similar to the type of service (ToS) field in the IPv4 header, the traffic class field (8 bits) is available for use by originating nodes and for forwarding routers to identify and distinguish between different classes or priorities of IPv6 packets.

Current Cisco IOS Software support for IPv6 QoS includes:
✑ Packet classification
✑ Queuing (includes LLQ; excludes legacy PQ/CQ)
✑ Traffic shaping
✑ WRED
IPv6 also has a 20-bit field known as the flow label field (RFC 3697). The flow label enables per flow processing for differentiation at the IP layer.
It can be used for special sender requests and is set by the source node.
The flow label must be modified by an intermediate mode.
Planned Cisco IOS Software support for IPv6 QoS includes:
✑ Compressed Real-Time Protocol (cRTP)
✑ Network-based application recognition (NBAR)
Committed access rate (CAR)
by designtshirt at April 3, 2025, 9 p.m.

Comments

Chosen Answer:
This is a voting comment (?). It is better to Upvote an existing comment if you don't have anything to add.
Switch to a voting comment New
Submit Cancel
Currently there are no comments in this discussion, be the first to comment!
Community vote distribution
A (35%)
C (25%)
B (20%)
Other
Most Voted
A voting comment increases the vote count for the chosen answer by one.

Upvoting a comment with a selected answer will also increase the vote count towards that answer by one. So if you see a comment that you already agree with, you can upvote it instead of posting a new comment.

SaveCancel